On a hot Tuesday morning following Labor Day in 1934, several hundred people crowded into the Caucus Room of the Senate Office Building to witness the opening of an investigation that journalists were already calling “historic.” Although World War I had been over for 16 years, the inquiry promised to reopen an intense debate about whether the nation should ever have gotten involved in that costly conflict.

The so-called “Senate Munitions Committee” came into being because of widespread reports that manufacturers of armaments had unduly influenced the American decision to enter the war in 1917. These weapons’ suppliers had reaped enormous profits at the cost of more than 53,000 American battle deaths. As local conflicts reignited in Europe through the early 1930s, suggesting the possibility of a second world war, concern spread that these “merchants of death” would again drag the United States into a struggle that was none of its business. The time had come for a full congressional inquiry.

To lead the seven-member special committee, the Senate’s Democratic majority chose a Republican—42-year-old North Dakota Senator Gerald P. Nye. Typical of western agrarian progressives, Nye energetically opposed U.S. involvement in foreign wars. He promised, “when the Senate investigation is over, we shall see that war and preparation for war is not a matter of national honor and national defense, but a matter of profit for the few.”

Over the next 18 months, the “Nye Committee” held 93 hearings, questioning more than 200 witnesses, including J. P. Morgan, Jr., and Pierre du Pont. Committee members found little hard evidence of an active conspiracy among arms makers, yet the panel’s reports did little to weaken the popular prejudice against “greedy munitions interests.”

The investigation came to an abrupt end early in 1936. The Senate cut off committee funding after Chairman Nye blundered into an attack on the late Democratic President Woodrow Wilson. Nye suggested that Wilson had withheld essential information from Congress as it considered a declaration of war. Democratic leaders, including Appropriations Committee Chairman Carter Glass of Virginia, unleashed a furious response against Nye for “dirtdaubing the sepulcher of Woodrow Wilson.” Standing before cheering colleagues in a packed Senate Chamber, Glass slammed his fist onto his desk until blood dripped from his knuckles.

Although the Nye Committee failed to achieve its goal of nationalizing the arms industry, it inspired three congressional neutrality acts in the mid-1930s that signaled profound American opposition to overseas involvement.